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Security Analysis of Data Method Using MIPS Encryption Algorithm (MEA) Sangeeta

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Security Analysis of Data Method Using MIPS Encryption Algorithm (MEA) Sangeeta Security Analysis of data Method using MIPS Encryption Algorithm (MEA) Sangeeta [email protected] ABSTRACT The MEA is an integral approach of block cipher and transposition cipher method. It takes 64 bit plain text input and produces 64 bit cipher text as in IDEA with modified key schedule to avoid possibilities of weak keys. It further makes transposition of the 64 bit cipher text to 128 bit end cipher text for disk storage. The increased length of end cipher text is a trade-off between the degree of increased security to SI and the nominal cost of storage media in the present state_of_the_art development. Keywords: Encryption, Decryption, Block cipher, Transposition cipher, MEA 1. INTRODUCTION Since PCs can be utilized to rapidly break credulous cryptosystems one should utilize encryption calculations that are free from and scientific shortcomings and that are computationally infeasible to break by making splitting additional tedious. In the meantime, the computational multifaceted nature of encryption and unscrambling ought to be inside sensible points of confinement since they speak to handling overheads too. One calculation that is accepted to give a sensible trade off among these necessities depends on the Data Encryption Standards (DES) [4,5,10]. For as far back as 20 years, the best security the greater part of us have caught wind of has been given by DES. In spite of the fact that there has been a shortcoming of shrouded trapdoors through s- encloses DES [6,10], still it has been a decent and secure calculation against the mid seventies innovations. Presently with the appearance of rapid PCs it is confronting more feedback for not sufficiently giving security due to its 56 bit key size. Some different calculations gave likewise been produced at the appointed time of time, for example, An Application of Chinese Remainder Theorem to Multiple-enter encryption in Database Systems[3] and A High Performance Encryption Algorithm [11] and so on.. These calculations likewise confront feedback for break because of existing break strategies like Brute power, Linear and Differential cryptanalytic techniques [14] and the advancement of high handling pace of PCs. Keeping in mind the end goal to stay away from any cryptanalytic assault on figure content as a result of little key length in DES [6,10] another outstanding calculation IDEA (International Data Encryption Algorithm) [13], on 128 piece key with a square figure technique has been produced. It gives an intense encryption that opposes to a break plausibility emerging from fast of PCs of today and propelled break strategies [14]. This calculation deals with 64 bit 575 | P a g e plain content information and produces 64 bit figure content. The outline theory behind this calculation is one of the blending activities from various arithmetical gatherings. In contrast with DES, the calculation IDEA is by all accounts a more secure proposition in light of its 128 piece key approach yet to what extent it can remain to the difficulties postured by cryptanalytic strategies and expanding velocity of PCs is as yet an inquiry. The security of a figuring framework is such a testing field, to the point that it requests presentation of more up to date thoughts ordinary. The present encryption calculation named as MIPS1 Encryption Algorithm (MEA) is a stage forward toward this path and gives encourage protection from break than IDEA. The Multilevel Information Protection System (MIPS) is an Information System which provides a relatively higher degree of security to a Sensitive Information (SI). The security to SI in MIPS is given by a MIPS Encryption Algorithm (MEA) and System Run Time Checker (SRTC): an Authentication module. The MEA works on user supplied 128 bit key whereas SRTC keeps monitoring of all unauthorized access on SI. II MIPS Encryption Algorithm (MEA) The MIPS Encryption Algorithm (MEA) chips away at symmetric key framework and is a change of IDEA [13] for more grounded encryption. It encodes SI in two passes. In the main pass it scrambles a contribution of 64 bit plain content (PT) in 64 bit figure content (CT2) utilizing square figure strategy with changed key timetable to take out frail keys of IDEA. The second pass changes over CT in end figure content (ECT) utilizing transposition figure strategy. The ECT at that point is utilized for capacity of encoded SI on circle. The expanded length of ECT can be viewed as an exchange off between the high security gave by this calculation and the ostensible cost of plate stockpiling media in current situation with the-workmanship advancement. The different strides of encryption/decoding of plain content in end figure content are appeared as takes after: Generation of encryption keys to encrypt PT in CT, Encryption of PT in CT, Encryption of CT in ECT, Decryption of ECT to CT, Generation of decryption keys to decrypt ECT to CT, Decryption of CT to PT 2.1 Generation of Encryption Keys to Encrypt PT in CT : The MIPS Encryption Algorithm is intended to encode SI in two passes. In the principal pass it scrambles a 64 bit plain content (PT) in 64 bit figure 576 | P a g e content (CT). It requires a sum of 52 encryption keys with 16 bits each as in IDEA [13]. These 52 encryption keys are created from client inputted 128 piece enter by isolating it into 8 encryption keys with 16 bits each. The 96 bits out of 128 bits i.e. 6 encryption keys are utilized as a part of round1 of pass1. CT is utilized for transmission over Computer Networks. The rest of the 32 bits are the initial two encryption keys for cycle 2. The 64 bits for four residual encryption keys of round2 are produced from coherent turn and Exclusive-OR task on encryption keys acquired from client provided 128 piece key. The third encryption key of round2 is produced from an Exclusive-OR task of 7 bits sensibly left pivoted first encryption key with legitimately 8 bits right turned second encryption key of round1. When all is said in done, the ith encryption key (9 < I < 52) is created from an Exclusive-OR activity of 7 bits legitimately left turned (I – 8)th encryption key with intelligently 8 bits right pivoted (I – 7)th encryption key. 2.2 Encryption of Plain Text in Cipher Text : Given a 64 bit plain text MEA converts it in a 64 bit cipher text as IDEA3 with modified key schedule. It uses one logical and two algebraic operations for encryption as follows : Exclusive OR i.e. xy = z, xz = y, yz = x Addition Modulo 216 (ignoring any overflow) i.e. Addition Modulo 216 of x and y is (x+y) & 65535 (& stands for masking) ; Multiplication Modulo 216+1 (ignoring any overflow) : We denote this operation as mul and show its result on two numbers x and y. This function is explained below : unsigned mul(x,y) unsigned x, y ; 3 We have changed the notations of IDEA as per our convenience. { long int p ; long unsigned q ; if (x == 0) { p = 65537 – y} else if (y = = 0) { p = 65537 – x } else { q = x * y ; p = (q & 65535) – (q >> 16) ; if (p <= 0) p = p + 65537 ; } return (unsigned) ( p & 65535) } ; The MEA divides 64 bit plain text data block in four sub-blocks as (pt1, pt2, pt3, pt4). It performs the operations as described above on these sub-blocks for eight rounds. After each round it produces four 577 | P a g e intermediate output sub-blocks as ct11, ct12, ct13, ct14. The sequence of operations in each round is as follows : (Notations :: : Exclusive OR, : multiplication modulo 216 + 1 and & : masking ) ct1 = pt1k1 ; ct2 = (pt2 + k2) & 65535 ; ct3 = )pt3 + k3) & 65535 ; ct4 = pt4 k4 ; ct5 = ct1 ct3 ; ct6 = ct2 ct4 ; ct7 = ct5 k5 ; ct8 = (ct8 + ct7) & 65535 ; ct9 = ct8 k6; ct10 = (ct7 + ct9) & 65535 ; ct11 = ct1 ct9 ; ct12 = ct3 ct9 ; ct13 = ct2 ct10 ; ct14 = ct4 ct10 ; Here, the intermediate output after round1 is the four sub-blocks ct11, ct12, ct13 and ct14. The input data block for round2 is produced by swapping two inner sub-blocks i.e. ct12 and ct13. Thus the input data block for round2 is (pt1, pt2, pt3, pt4) such that : pt1 = ct11 ; pt2 = ct13 ; pt3 = ct12 ; pt4 = ct14 ; This input (pt1, pt2, pt3, pt4) is encrypted by using the encryption keys of round2 with a similar set of operations as performed above in round1. This process of encryption should be repeated for 8 rounds. The final output after round8 will have following operations : ct1 = pt1 k1; ct2 = (pt2 + k2) & 65535 ; ct3 = (pt3 + k3) & 65535 ; ct4 = pt4 k4 ; Thus, MEA outputs 64 bit cipher text (ct1, ct2, ct3, ct4) from the plain text (pt1, pt2, pt3, pt4) at the end of pass 1. 2.3 Encryption of Cipher Text in End Cipher Text : The pass 2 of the MEA converts 64 bit cipher text in 128 bit end cipher text (figure 1). We apply transposition cipher method in this pass. The input for this 8 pass is the end product of pass1 i.e. cipher text {(ct1, ct2, ct3, ct4) where each cti is of 16 bits}. We apply 2 modulo operation on each 16 bit sub-block of cipher text to split it into two components. Likewise all four sub-blocks of cipher text are split as under : ct1 = (ct11, ct12) ; ct2 = (ct21, ct22) ; ct3 = (ct31, ct32) ; ct4 = (ct41, ct42), 8 8 Here cti1 = cti mod 2 and cti2 = cti1 ((cti – cti1) / 2 ), [ : Exclusive – OR]. Thus the input block produced for transposition in pass2 is a 128 bit block (ct11, ct12, ct21, ct22, ct31, ct32, ct41, ct42).
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